package
{
    
    import flash.display.BitmapData;
    import flash.display.BlendMode;
    import flash.display.DisplayObject;
    import flash.display.Sprite;
    
    import flash.geom.ColorTransform;
    import flash.geom.Matrix;
    import flash.geom.Point;
    import flash.geom.Rectangle;
    
    public class HitTest
    {

        public static function complexHitTestObject( target1:DisplayObject, target2:DisplayObject,  accuracy:Number = 1 ):Boolean
        {
            return complexIntersectionRectangle( target1, target2, accuracy ).width != 0;
        }
        
        public static function intersectionRectangle( target1:DisplayObject, target2:DisplayObject ):Rectangle
        {
            // If either of the items don't have a reference to stage, then they are not in a display list
            // or if a simple hitTestObject is false, they cannot be intersecting.
            if( !target1.root || !target2.root || !target1.hitTestObject( target2 ) ) return new Rectangle();
            
            // Get the bounds of each DisplayObject.
            var bounds1:Rectangle = target1.getBounds( target1.root );
            var bounds2:Rectangle = target2.getBounds( target2.root );
            
            // Determine test area boundaries.
            var intersection:Rectangle = new Rectangle();
            intersection.x         = Math.max( bounds1.x, bounds2.x );
            intersection.y        = Math.max( bounds1.y, bounds2.y );
            intersection.width     = Math.min( ( bounds1.x + bounds1.width ) - intersection.x, ( bounds2.x + bounds2.width ) - intersection.x );
            intersection.height = Math.min( ( bounds1.y + bounds1.height ) - intersection.y, ( bounds2.y + bounds2.height ) - intersection.y );
        
            return intersection;
        }
        
        public static function complexIntersectionRectangle( target1:DisplayObject, target2:DisplayObject, accuracy:Number = 1 ):Rectangle
        {            
            if( accuracy <= 0 ) throw new Error( "ArgumentError: Error #5001: Invalid value for accuracy", 5001 );
            
            // If a simple hitTestObject is false, they cannot be intersecting.
            if( !target1.hitTestObject( target2 ) ) return new Rectangle();
            
            var hitRectangle:Rectangle = intersectionRectangle( target1, target2 );
            // If their boundaries are no interesecting, they cannot be intersecting.
            if( hitRectangle.width * accuracy < 1 || hitRectangle.height * accuracy < 1 ) return new Rectangle();
            
            var bitmapData:BitmapData = new BitmapData( hitRectangle.width * accuracy, hitRectangle.height * accuracy, false, 0x000000 );    

            // Draw the first target.
            bitmapData.draw( target1, HitTest.getDrawMatrix( target1, hitRectangle, accuracy ), new ColorTransform( 1, 1, 1, 1, 255, -255, -255, 255 ) );
            // Overlay the second target.
            bitmapData.draw( target2, HitTest.getDrawMatrix( target2, hitRectangle, accuracy ), new ColorTransform( 1, 1, 1, 1, 255, 255, 255, 255 ), BlendMode.DIFFERENCE );
            
            // Find the intersection.
            var intersection:Rectangle = bitmapData.getColorBoundsRect( 0xFFFFFFFF,0xFF00FFFF );
            
            bitmapData.dispose();
            
            // Alter width and positions to compensate for accuracy
            if( accuracy != 1 )
            {
                intersection.x /= accuracy;
                intersection.y /= accuracy;
                intersection.width /= accuracy;
                intersection.height /= accuracy;
            }
            
            intersection.x += hitRectangle.x;
            intersection.y += hitRectangle.y;
            
            return intersection;
        }
        
        
        protected static function getDrawMatrix( target:DisplayObject, hitRectangle:Rectangle, accuracy:Number ):Matrix
        {
            var localToGlobal:Point;;
            var matrix:Matrix;
            
            var rootConcatenatedMatrix:Matrix = target.root.transform.concatenatedMatrix;
            
            localToGlobal = target.localToGlobal( new Point( ) );
            matrix = target.transform.concatenatedMatrix;
            matrix.tx = localToGlobal.x - hitRectangle.x;
            matrix.ty = localToGlobal.y - hitRectangle.y;
            
            matrix.a = matrix.a / rootConcatenatedMatrix.a;
            matrix.d = matrix.d / rootConcatenatedMatrix.d;
            if( accuracy != 1 ) matrix.scale( accuracy, accuracy );

            return matrix;
        }

    }

}